Many of the veterans who served in the Gulf War have subsequently developed somatic and psycological symptoms. Some veterans' symptoms are clearly due to known disorders such as posttraumatic stress disorder (PTSD) but many others are experiencing a broad array of symptoms which defy diagnostic classification. To evaluate whether symptoms in Gulf War veterans (GWVs) are related to a stress disorder, we propose to study psychobiologic alterations in GWVs using the same neuroendocrinologic methods that have proven useful in elucidating the pathophysiology of PTSD in Vietman veterans. We aim to determine whether PTSD is associated with neuroendocrine alterations in GWVs and whether other health symptoms in these veterans are associated with neuroendocrine alterations.